Fuel cells have been proposed as a power source for many applications, for example, as a primary power source in vehicles and the like. To meet customer expectations in vehicle applications, the fuel cell should be capable of quick start-up. At relatively high ambient temperatures (e.g. about 20° C. or above) a fuel cell stack, which may include a plurality of individual fuel cells bundled together, can be started and reach acceptable operating conditions in a reasonable amount of time. In some applications, the preferred operating temperature may be around 80° C.
At relatively low temperatures, such as subfreezing temperatures of about −25° C., rapid startup of the fuel cell stack is more difficult because at these temperatures the rate at which the overall electrochemical reaction occurs is significantly reduced. This limits the amount of current that can be drawn from the stack and the resultant heat output by the stack. The reduced output of the fuel cell stack can degrade drive-away performance of the vehicle, as well as slow the rate at which the interior vehicle cabin can be heated, the rate at which windshield defrost mechanisms operate, and the like.